Dr Krissy Haglund does not care if she is labeled a socialist. Or an ideological purist . Or, indeed, any of the other epithets thrown at Americans who are flocking to support Bernie Sanders for the Democratic presidential nomination. She knows what she is: fed up.

“I have patients who are deciding not to have children or are unable to buy a house because of their student loans,” says the family physician from Minneapolis , who this week drove four hours with two young offspring of her own to see the senator speak in Iowa.

“My loan is now $283,000. It’s gone up $60,000 in the six years since I graduated from medical school. This is a national crisis that needs deep, immediate attention.”

As the only candidate proposing to abolish tuition fees at public universities, Sanders frequently takes on the role of a reverse auctioneer, asking members of the audience at his rallies to shout out how much student debt they have. For a while, the record was $300,000. Then he met a dentist who graduated with loans of $400,000.

But paying for college by taxing Wall Street speculation is not the only policy that has seen the senator from Vermont branded a dangerous extremist – by his own party. Despite the limited health insurance reforms passed by Barack Obama, 29 million Americans remain without any coverage and many more are underinsured to the point where they cannot afford to see a doctor.

So Sanders does the same thing with healthcare, asking audiences to compete to reveal the size of their deductible – the fixed amount per treatment that must be paid by patients before their insurer will contribute anything. At almost every rally someone gets up to $5,000, sometimes in tears.

The plan to replace this bureaucratic and expensive system by expanding the public Medicare program emulates a “single payer” insurance model used in Canada, rather than the direct state provision of Britain’s National Health Service. It aims to reduce overall costs caused by hospitals and drug companies charging the weak US consumer many times the equivalent in other countries that benefit from pooled purchasing power.

Nevertheless, when inevitably someone asks if the US can afford to follow other rich countries down the road of universal healthcare and access to tertiary education, Sanders likes to remind them of the trillions of dollars of income redistribution that has already taken place in the opposite direction: a trend that has left median wages slumping, but 58% of all new income since the banking crash going to the top 1%.

A few years ago you could graduate high school and get a job and j… you’d be able to achieve whatever you wanted

Anna Mead, 22, student

“Enough is enough,” audience members typically roar by the time he reaches this point in the well-worn speech.

“A few years ago you could graduate high school and get a job and just work hard, put on those work boots, and you’d be able to achieve whatever you wanted,” agrees Anna Mead, 22, a student from Long Beach, New Jersey, outside a rally in New Hampshire.

“Now, it’s just not the case anymore. We’ve seen vast amounts of inequality just building and building throughout the decades to the extent that the 1% has accumulated such a vast amount of wealth that exceeds 40% of the population. I feel like the United States has always been strengthened whenever we had a president take any kind of policy for the middle class to build them up. When you build everyone up, everyone does better.”

The notion, proposed by Sanders, that a corrupt campaign finance system is the only thing standing between voters and a once-in-a-lifetime opportunity to change this might seem simplistic. But it is proving wildly popular.

From a standing start, he has closed the gap in the Democratic primary race between himself and a once unassailable Hillary Clinton, from 36% to just 2%, according to a national poll this week.

Sanders is so far ahead of the former secretary of state in New Hampshire polls that her advisers would be delighted if they can contain his win to single digits, in the first primary on Tuesday. Many are already dismissing the result as a home turf blip and encouraging her to leave the state on Sunday to focus her time elsewhere.

Locals in New Hampshire bristle, though, at the notion they would be swayed simply because someone is from Vermont, a liberal bastion that the more libertarian iconoclasts in the Granite State regard suspiciously.

The argument also ignores the fact that the state Hillary Clinton represented in Congress is only 50 miles from the border. New York may have its own cultural differences with New England, but it is home to Clinton’s campaign headquarters in Brooklyn and is reportedly so ambiguous about its former senator that the Sanders camp claim she refused their requests to hold a debate there.

Yet much as it pains his supporters to acknowledge any frailty , Sanders is under growing pressure from Clinton during their debates. The attack strategy varies. Sometimes she argues they are dancing on the head of a pin by debating who is a true progressive, but when the policy gulf is illuminated the attack switches to what she claims are his wildly unrealistic proposals.

Privately, Clinton’s attack machine has gone further, claiming deep-seated communist sympathies . It serves as a likely prelude to what Sanders might face from Republicans in the still somewhat unlikely event that he wins the Democratic primary.

Sanders has never hidden his political background and has left much for critics to pick over. But it is his steadfast determination not to run from the label “democratic socialist” that causes most confusion.

I don’t know what we mean when we say he is a socialist because my idea of Bernie Sanders is that he’s an FDR liberal

Sharon Ranzavage, 69, attorney

In a lengthy speech at Georgetown University last November , he argued that his political philosophy was most in keeping with that of Franklin D Roosevelt, who similarly proposed a mix of public works, help for the poor and banking reform to lift America from the Great Depression.

“I don’t know what we mean when we say he is a socialist because my idea of Bernie Sanders is that he’s an FDR liberal,” agrees Sharon Ranzavage, 69, an attorney from Flemington, New Jersey, speaking outside an event in Manchester, New Hampshire on Friday.

“He’s back to the future if you will and that’s why I’m excited about him. I think the Democratic party in this country has veered very far to the right. We have to get back to who we are, which is taking care of each other. We’re a capitalist country but we need to modify the extremes of capitalism.”

Confusion also stems from the fact that Sanders uses the phrase “democratic socialist” partly to stress his belief that change must come through the ballot box, but also because, in continental Europe at least, he would probably be known as a social democrat, a label that does not easily translate.

A “Democrat” in US parlance is something the independent senator from Vermont only became when he decided to seek the party’s presidential nomination in May. Anyone using the word “social” in American politics might as well go the whole hog and add the “ist” before somewhere else does.

In a British context, Sanders is hard to place too. Many of his core proposals – universal access to healthcare, paid maternity leave and a more generous minimum wage – are accepted, in principle at least, by all the main UK parties including the Conservatives, who recently put up the British minimum wage as a centerpiece of their budget.

In relative terms, Sanders represents a swing to the left for the Democratic party that is analogous to Jeremy Corbyn’s recent victory in the Labour leadership campaign. But on foreign policy and absolute comparisons of domestic policies he would probably be closer to pre-Blairite Labour reformers such as Neil Kinnock or John Smith.

Back in New Hampshire this week, a radical mood is conjured up at rallies calling for a “political revolution” and blasting out John Lennon’s Power to the People. But when Sanders punches his hand into the air, he quickly unclenches the fist, to avoid imagery that is too strident.

We will have to wait for several more primary results to know whether American politics could possibly be ready for a self-avowed socialist. Already, the response from supporters to seem to be a shrug that suggests this is the wrong question.

“I feel like I finally have a politician who will match my true feelings and hopes for this country,” says Dr Haglund.

Is America ready for socialism? Probably not. But it might be ready for Sanders.